The play, which enraged 49ers coach Jim Harbaugh both on the field in the media this week, came on the tail end of Matthews launching into Kaepernick near the sideline on the tail end of a third-and-6 scramble with 9 minutes, 30 seconds left in the first half.

The NFL ruled the fine was for “striking an opponent late." Matthews received a $20.5 million signing bonus with his extension this offseason, but his $1.02 million base salary means his fine will run him a quarter of his $60,000 game check.

Harbaugh retaliated on Monday by suggesting Matthews was a dirty player, a notion Packers coach Mike McCarthy and defensive coordinator Dom Capers have since refuted.

Matthews was sheepish when defending himself on Thursday, reiterating that he wants to focus on Sunday’s game against Washington before he finally retorted, “I’m an awesome player, not a dirty player.”

The only other fine Matthews could remember was a face-mask penalty against Chicago quarterback Jay Cutler in 2010, which he was fined $5,000 for.

It appeared the Packers pulled Matthews from the game momentarily as he started the next defensive series on the sideline for the first three plays before re-entering following a delay of game penalty on the 49ers on third down, but Packers outside linebackers coach Kevin Greene said that wasn’t the case.

“I don’t think it was anything – you need to go sit on the bench. You’re going to the principal’s office kind of thing. I don’t think it was that,” Greene said.

Greene said he hasn’t discussed the late hit with Matthews in great detail, but admitted the hit was an unnecessary mistake. He wants his outside linebackers to continue to play “amped up with an edge and aggressive,” but also within the boundaries of the rule book.

“It’s football. Having played 15 years in the league, football is football,” Greene said. “We make mistakes in everything we do. We’re not robots. Hey, we learn from our mistakes and move on. That’s everything. That’s just one of the little mistakes we made as an outside linebacker unit.”

Matthews was the only Packers player to come out of Sunday’s loss with a lighter wallet, but two 49ers players – linebacker Ahmad Brooks and receiver Anquan Boldin – also picked up fines from the NFL.

Brooks was fined $12,750 for a roughing the passer penalty committed on Aaron Rodgers later in the second quarter after Matthews’ hit on Kaepernick.

Boldin was docked $7,850 for a late hit on Packers cornerback Jarrett Bush on another Kaepernick third-down sideline scramble in the third quarter. The play went for a first down, but Boldin’s hit went uncalled with the league fine serving as an indication it should’ve been.

As for Matthews’ error in judgment, the Packers are prepared to put it behind them.

“It’s obviously a mistake,” Greene said. “I believed Clay has addressed that and we’ve moved on.”